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Gun Metal - Raku Glaze

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#1 ayjay


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Posted 07 July 2013 - 06:36 AM

I was looking around for some Raku glazes to make up for a forthcoming session and came across a recipe called "Gun Metal"  - I've actually found it in two different versions on the net  - the proportions are the same in each but neither of them say whether it is by weight or volume - the second version suggests to me that it is by weight. 


Is anybody familiar with this glaze and able to confirm that? 


Gerstley Borate . 3 parts                               

Neph Sye  ......... 1 part

Copper Carb.   . .3 parts

RiO  ...... ....  .  .  3 parts


Gerstley Borate 75

Neph Sye . ....... 25

Copper Carb..    75

RiO  ...... ....    ...75






#2 Marcia Selsor

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Posted 07 July 2013 - 06:49 AM

The first suggests it is by volume. I have a couple of Raku glazes by volume. I would test both ways.



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#3 Kohaku


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Posted 07 July 2013 - 09:45 AM

What Marcia said. Post a picture when you've tested!

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#4 ayjay


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Posted 07 July 2013 - 01:51 PM

I agree the first suggests it's by volume (but could still be by weight) and is probably how I'll try it first - but  the second gives what seems to be an actual amount.


How would 75 & 25 (presumably grams or ounces) relate to a volume measurement.


........(or am I just having a senior moment and missing something). :blink:

#5 Nancy S.

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Posted 07 July 2013 - 02:02 PM

Seems to me that the 75/25 could be amounts. 75 is 3 parts; 25 is one part.


I don't know if this helps at all....and it still doesn't explain whether it's volume or weight. Usually when mixing drinks or baking, it's a volume thing. But with glazes, it's usually a weight thing. And with dry, powdery materials, there can be a big difference between weighing and measuring.


That said, I've never seen a glaze recipe with "parts" or proportions like this. Maybe try it both ways (in small amounts) and test it out?

#6 Rakuken


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Posted 07 July 2013 - 07:58 PM

The second recipe I've mixed by weight, 75 grams GB and 25 grams neph sy is OK. But I question the weight of the copper carb and rio, would it be .75?

Aloha, Ken

#7 TJR


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Posted 07 July 2013 - 10:45 PM

I am thinking the recipe should be as follows;

Ger borate 75 grams

Neph Sy     25 grams

This totals 100%

Then add copper carb 3%

R.I.O.                           3%

In a 100 gram batch the colourants will each be 3 grams.

100 grams of glaze is about a paper cup full when you add water.

To make a 5 gallon pail of glaze, you would need 10,000 grams of glaze.

A plastic ice-cream pail would be 1000 grams.


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